.net - 在 WCF 中序列化 SQLParameter 的任何解决方案或解决方法？

Question

我最初在 MessageContract 中定义了 SQLParameters 集合，以便通过 WCF 服务创建简单的存储过程执行。显然，SQLParameter 类型不可序列化，因此我需要一些有关如何继续此处的建议。

是否仍然可以以某种方式使用 SQLParameter 作为我的 WCF 合约的一部分，或者我必须执行其他操作，例如创建一个与 SQLParameter 具有相同属性的自定义类，然后在代码中的其他位置创建 SQLParameters？

更新:
为了进一步了解为什么会出现这种情况，最初 Windows 窗体客户端使用常用的 ADO.NET 对象直接连接到数据库以检索用于报告目的的数据集。现在，客户想要一个通用的 Web 服务来处理所有报告。这是我能想到的最好的处理方法，无需进行太多更改。

Answer 1

我对以下已接受的答复感到相对平淡:

You might find you want to refactor those further, to reduce the number or increase the level of abstraction. But if not, then you should then do the equivalent of extracting all of those methods into one or more interfaces. Those interfaces would become the ServiceContracts for your WCF service. Move the methods into the new services to implement these service contracts, and you're pretty much done.

从根本上来说，这是对简单的预定义业务逻辑的正确响应；然而，对于不同的抽象级别，例如运行临时 sql 查询所需的服务，不能简单地通过预定义的服务调用来提供这种级别的灵 active 。

对于在 WCF 服务环境中工作的临时查询，必须传递参数，以保护系统并防止各种 SQL 注入(inject)式攻击媒介。

举个例子，我构建了一项服务，作为业务需求，需要将数据层从客户端抽象出来，并允许第三方与不同数据库系统上的多个数据库进行交互。

对于这个系统，我采用了上述 Craig H 的方法，并创建了一个 SerializedSqlParam 类作为列表对象传递给我的服务。

我的SerializedSqlParam类的好处如下:

1. SqlParameter 类的直接序列化和类型转换。
2. 序列化对象以 UTF-16 字符串格式存储，以允许 SQL server to save the objects .
3. 正确使用 AssemblyQualifiedName 以允许反序列化不在直接程序集中的对象。
4. 完成 SqlParameter 类参数的编码。

一般用法如下:

SerializedSqlParam sp = new SerializedSqlParam(new SqlParameter("@id", 1));

//or through typecasting:

SqlParameter parameter = new SqlParameter("@id", 1);
SerializedSqlParam sp = (SerializedSqlParam) parameter;

要反序列化，只需执行以下操作:

SqlParameter parameter = sp.GetSqlParameter();

//or through typecasting

SqlParameter parameter = (SqlParameter) sp;

这是我的类(class)。我确信有些事情可以修复/改进；然而，这只是为了让大家理解这个概念。希望其他读者会发现这有帮助!

SerializedSqlParam.cs

[DataContract]
public class SerializedSqlParam
{
    [Browsable(false)]
    [DataMember]
    public string CompareInfo { get; set; } 

    [RefreshProperties(RefreshProperties.All)]
    [DataMember]
    public string Direction { get; set; }

    [DataMember]
    public bool IsNullable { get; set; }

    [Browsable(false)]
    [DataMember]
    public int LocaleId { get; set; }

    [Browsable(false)]
    [EditorBrowsable(EditorBrowsableState.Advanced)]
    [DataMember]
    public int Offset { get; set; }

    [DataMember]
    public string ParameterName { get; set; }

    [DefaultValue(0)]
    [DataMember]
    public byte Precision { get; set; }

    [DefaultValue(0)]
    [DataMember]
    public byte Scale { get; set; }

    [DataMember]
    public int Size { get; set; }

    [DataMember]
    public string SourceColumn { get; set; }

    [DataMember]
    public bool SourceColumnNullMapping { get; set; }

    [DataMember]
    public string SourceVersion { get; set; }

    [DataMember]
    public string SqlDbType { get; set; }

    [DataMember]
    public string TypeName { get; set; }

    [DataMember]
    public string UdtTypeName { get; set; }

    [DataMember]
    public string Value { get; set; }

    [DataMember]
    public string ValueType { get; protected set; }

    [DataMember]
    public string XmlSchemaCollectionDatabase { get; set; }
    [DataMember]
    public string XmlSchemaCollectionName { get; set; }
    [DataMember]
    public string XmlSchemaCollectionOwningSchema { get; set; }

    public SerializedSqlParam(SqlParameter p)
    {
        this.CopyProperties(p);
        this.SerializeParameterValue(p);
    }

    public static explicit operator SerializedSqlParam(SqlParameter p)
    {
        return new SerializedSqlParam(p);
    }

    public static explicit operator SqlParameter(SerializedSqlParam p)
    {
        return p.GetSqlParameter(p);
    }

    public SqlParameter GetSqlParameter()
    {
        return this.GetSqlParameter(this);
    }

    public SqlParameter GetSqlParameter(SerializedSqlParam serialized)
    {
        SqlParameter p = new SqlParameter();

        p.ParameterName = serialized.ParameterName;
        p.Precision = serialized.Precision;
        p.Scale = serialized.Scale;
        p.Size = serialized.Size;
        p.IsNullable = serialized.IsNullable;
        p.LocaleId = serialized.LocaleId;
        p.Offset = serialized.Offset;
        p.SourceColumn = serialized.SourceColumn;
        p.SourceColumnNullMapping = serialized.SourceColumnNullMapping;

        p.XmlSchemaCollectionDatabase = serialized.XmlSchemaCollectionDatabase;
        p.XmlSchemaCollectionName = serialized.XmlSchemaCollectionName;
        p.XmlSchemaCollectionOwningSchema = serialized.XmlSchemaCollectionOwningSchema;

        p.TypeName = serialized.TypeName;
        p.UdtTypeName = serialized.UdtTypeName;

        p.Direction = (ParameterDirection)Enum.Parse(typeof(ParameterDirection), serialized.Direction);
        p.CompareInfo = (SqlCompareOptions)Enum.Parse(typeof(SqlCompareOptions), serialized.CompareInfo);
        p.SourceVersion = (DataRowVersion)Enum.Parse(typeof(DataRowVersion), serialized.SourceVersion);

        p.Value = this.DeserializeObject(serialized.Value, Type.GetType(serialized.ValueType));

        return p;
    }

    private void SerializeParameterValue(SqlParameter p)
    {
        if (p.Value.GetType().IsSerializable)
        {
            this.ValueType = this.GetTypeAssemblyQualifiedName(p.Value);
            this.Value = this.SerializeObject(p.Value);
        }
        else
        {
            throw new SerializationException("Cannot serialize the parameter value object. Recast that object into a primitive or class that can be serialized.");
        }
    }

    private void CopyProperties(SqlParameter p)
    {
        this.ParameterName = p.ParameterName;
        this.Precision = p.Precision;
        this.Scale = p.Scale;
        this.Size = p.Size;
        this.IsNullable = p.IsNullable;
        this.LocaleId = p.LocaleId;
        this.Offset = p.Offset;
        this.SourceColumn = p.SourceColumn;
        this.SourceColumnNullMapping = p.SourceColumnNullMapping;

        this.XmlSchemaCollectionDatabase = p.XmlSchemaCollectionDatabase;
        this.XmlSchemaCollectionName = p.XmlSchemaCollectionName;
        this.XmlSchemaCollectionOwningSchema = p.XmlSchemaCollectionOwningSchema;

        this.TypeName = p.TypeName;
        this.UdtTypeName = p.UdtTypeName;

        this.Direction = p.Direction.ToString();
        this.CompareInfo = p.CompareInfo.ToString();
        this.SourceVersion = p.SourceVersion.ToString();

        try
        {
            this.SqlDbType = p.SqlDbType.ToString();
        }
        catch
        {
            this.SqlDbType = null;
        }
    }

    private string SerializeObject(object value)
    {
        if (value == null) return null;

        XmlSerializer serializer = new XmlSerializer(value.GetType());
        XmlWriterSettings settings = new XmlWriterSettings();

        settings.Encoding = new UnicodeEncoding(false, false);
        settings.Indent = false;
        settings.OmitXmlDeclaration = false;

        using (StringWriter textWriter = new StringWriter())
        {
            using (XmlWriter xmlWriter = XmlWriter.Create(textWriter, settings))
            {
                serializer.Serialize(xmlWriter, value);
            }
            return textWriter.ToString();
        }
    }

    private object DeserializeObject(string xml, Type type)
    {
        if (string.IsNullOrEmpty(xml)) return null;

        XmlSerializer serializer = new XmlSerializer(type);

        XmlReaderSettings settings = new XmlReaderSettings();
        using (StringReader textReader = new StringReader(xml))
        {
            using (XmlReader xmlReader = XmlReader.Create(textReader, settings))
            {
                return Convert.ChangeType(serializer.Deserialize(xmlReader), type);
            }
        }
    }

    private string GetTypeAssemblyQualifiedName(object obj)
    {
        return obj.GetType().AssemblyQualifiedName.ToString();
    }
}